Illuminating indicating instruments



Feb. 1942, -M KLEIN vE-l- AL 2,272,806

ILLUMINATING IDIGATING INSTRUMENTS Filed Nov. 29, 19:58 2 sheets-sheet 1 Feb.1o,1942. M, KLEM EN; 2,272,806

ILLUMINATING INDICATING INSTRUMENTS Filed Nav. 29, 1958 21sheets-sneet2 L j VBLUMQQNTROL Patented Feb. l0, 1942 @srA'rEis PATENT OFFICE flil AT ING INDCATING INSTRUMENTS an Klein, Sellersville, and William E. i Pfeifer, South Perkasie, Pa., assignors to United States Gauge Company, Sellersville, corporation oi Pennsylvania Pa., a

Application November 29, 1938, Serial No. 243,045

Claims.

`by an operator seated or otherwise stationed in front of the instrument board. It is often diilcult from the operators position to properly read such instruments at night due to improper lighting of the dial of the instrument principally because the instruments are lighted in a group or groups instead of individually. Furthermore, when such instruments are mounted, particularly in thedashboards of automobiles, aeroplanes and the like, it has been impossible to adequately illuminate the pointers moving over the dials so that a quick glance Will enable a reading of the instrument though undesired glare is avoided.

Frequently, under present illumination praetices, the light from the sources of illumination, when sufficient to adequately light the dials and pointers, casts undesirable shadows or glares in the eyes of the operator so that the view from his seat through the windshield is seriously impaired.

It is, accordingly, the primary object of the present invention to provide a novel system of illumination whereby the dial of an instrument is adequately illuminated while preventing undesired distribution of light in the region of the instrument.

A further object of the presentv invention resides in a system of indirect illumination of instruments wherein an indicia bearing element is illuminated by diffusing the light into the i11- terior of the element and across the face of the element to flood the area in which the pointer the divergent rays of light and direct theml against the reflecting surface of a wedge-shaped prism to spread the reflectedrays over a substantial area of the edge of the indicia bearing f element to eiect edge-illumination and/or over an arc parallel to and immediately adjacent a face of the indicia bearing element to effect edgeillumination and indirect lighting of a pointer or shadows regardlessof the position of the pointer or the like.

A still further'object of the present invention resides in the provision of a light shield disposed between a source of light and the edge of the dial of an instrument to prevent the direct transmission of light to the exterior of the instrument and in the provision of optical devices to divide the rays of light into a plurality of parallel areas, one of which includes the indicia bearing element and the other of which is parallel to a face of the indicia bearing element and includes a reflecting member arranged to cause an even diiusion of light in every direction parallel to said face.

A further object of the present invention resides in so coating the surfaces of the indicia bearing element of an instrument that the light,

diffused through the body of said element, illuminates merely the significant indicia on said element without reecting any substantial amount of light from the instrument.

Another object of the present invention resides Y Other objects will appear from this description and the appended claims when read in connection with the attached drawings wherein:

Figure 1 is a plan view of an instrument having a dial and pointer illuminated by the lighting system of the present invention, the cover glass and associated structure being removed for clarity of illustration;

Figure 2 is a transverse view in partial section taken on line 2 2 of Figure 1 and `looking in the direction of the arrows;

Figure 3 is a fragmental sectional view take on line 3-3 of Figure 1;

Figure 4 is a. fragmental sectional view showing a modified mounting for the light source;

Figure 5 is a top plan view of the parts'appearing in Figure 4;

Figure 6 is a fragmental sectional view illustrating a further modified form of the invention;

Figure 7 is a plan view similar to Figure 1 illustrating a further modified form of the invention.

Figure 8 is a partial sectional view taken on line 3-8 of Figure 7; and

Figure 9 illustrates the present invention applied to an indicia bearing panel, such as a radio control panel.

With continued reference to the drawings wherein like reference numerals are employed to the like disposed in said area without causing designate the'same parts throughoutthe several figures of the drawings, numeral I indicates generally an indicating instrument of any desired character such as a suction responsive gauge, a pressure gauge, a speedometer, a clock or the like.

Instrument I0 comprises a casing preferably of Bakelite or the like having the usual cover-glass I2 and pointer actuation mechanism I3, indicated by a box-like member carrying a dial I4. The instrument may be provided with any suitable means, .such as nuts I5, for mounting it on a supporting structure.

To adapt instrument I0 for the system 0f illuminatlon provided by this invention, casing II is provided with a rearwardly extending boss i6 which is designed to receive a suitable electrical socket I1 for connection to a source of electrical energy, and a boss I8 forming a bulb-socket connected by a suitable electrical conduit I9 to socket I1.

Conduit I9 may take any desired form but end of wire 2| is then passed through a suitable aperture 25 in the casing into bore 2l in boss I8 where it is connected to live conduit 28 which is provided with a concentric ring-shaped contact portion 29.

The portion 24 of sheathing 23 is soldered to one end of a conduit member which passes through a suitable aperture 3| in casing into bore 21 wherein it is connectedto return conduit 32. Apertures 26 and 3| are preferably sealed by any suitable material in order to render the cases pressure tight and to secure the electrical conduits in place. Conduit 32 is suitably connected to an annular tapped contact ring 33' which serves as the ground or return contact.

A suitable miniature light bulb 35, is inserted into the socket of boss I8 and makes contact with live contact ring 29 carried by conduit 2B through contact member 36. A protecting cap 31 is screwed into contact ring 33 and completes the contact between ring 33 and contact 38 of bulb 35. Cap 31 also serves to retain bulb 35 in place under suiiicient pressure to assure good electrical connections with the socket contacts. A more detailed disclosure of a bulb suitable for this purpose may be found by reference to the copending applications of Maximilian Klein and William E. Pfeffer entitled Miniature bulb and socket construction Serial Nos. 243,047 and 243,048 filed on even date herewith, now matured respectively into Patents No. 2,210,764 dated August 6, 1940, and No. 2,190,875 dated February 20, 1940.

Live conduit 28 intermediate contact ring 29 and its connection to wire 25 has lan enlarged area 38a providing securing arms 39 designed to engage an insulating sleeve 4|. Sleeve 4I snugly fits bore 21 and serves to maintain conduits 23 and 32 in their proper notches 42 and to locate ring 28 in its proper position. For a more'detailed disclosure of the casing and wiring structure, reference may be made to copending application of Maximilian Klein and William E. Pfeffer entitled Individually illuminated instrument casings" 243,046 led on even date herewith wherein this structure is specifically clalmed.`

In the modification shown in Figures 1v to 3, casing II is provided with a Wedge-shaped aperture 43, the upper edge of which coincides with the bottom of sleeve 4|. The smaller end of the aperture intersects bore 21 while the larger end intersects the interior of the casing. A wedgeshaped prism 44 corresponding in shape to aperture 43 is disposed in the aperture with its smaller end protruding into and extending slightly more than half way across bore 21. Prism 44 is provided with an external reflecting surface 45. A suitable cement, such as Glyptol lacq'uer, secures prism 44 in place. Reiecting surface 45 is of arcuate shape in plan and slopes inwardly from top to bottom at an angle of 45 so that the light rays from bulb will undergo total reection and pam through prism 44 at right angles to the axis of bore 21.

To insure an evenly distributed reflection of the light rays from bulb 35, a bulls-eye lens is secured by Glyptol lacquer in the lower end oi sleeve 4| so as to rest upon the upper surface of prism44. Lens 46 is so designed that the normally divergent light rays from bulb 35 will be reflected so as to leave the. exit face of lens 46 in a direction paralleling the axis of bore 21.

To secure the highly efficient illumination of the indicia bearing element, as contemplated by this invention, the panel or dial I4 of the instruments of Figures 1 through 7 are manufactured and positioned in the following manner:

Dial I4 is made of a crystal clear substance, for example, P1exiglas, which is an acrylic resin or Lucite which is a polymerized derivative of .methacrylic acid. Either of these materials are available on the open market in sheet form.

The dial I4, or panel of desired configuration, is cut from a sheet of the material and suitably treated to provide an element having its rear surface and edges coated with a fairly heavy coating of white paint 49, except for a uted portion 50 of the edge adjacent the exit face of prism 44. This portion 50 is left free of paint and is provided with vertically extending grooves or uting. The face of the dial contains a relatively thin coat of whitepaint 49 and is printed over with a black ink to form an opaque coating 5| except in the area of the markings, iigures, etc., which are left white. Certain of these white markings etc., may be then treated with radium 52 in the usual manner if desired.

The pointer 53 is also constructed of similar material. The indicating portion of pointer 53 is preferably of substantially triangular shape in cross-section with a flat face of the triangle serving as the underside. This facek is provided along each longitudinal edge with a series of parallel, transverse grooves or utings 54 and the upper surface is coated with a thin coatv of white paint, and may be radium treated after the manner of the markings, etc., of the dial if desired.

For a more detailed disclosure of the panel or dial and pointer, references may be had to the copending application of Maximilian Klein and William E. Pfeifer entitled Illuminable panel, dial and pointer structures" 243,044 filed on even date herewith wherein the dial and pointer are specifically claimed.

Casing II adjacent the dial I4 is provided with a shallow annular shoulder 56 which is designed to receive a corrugated metal reector 51. Reector 51 is preferably flexible, yet rigid enough to retain its position when placed on shoulder to cause a glare.

-Of the dial.

hooked in the opposite ends of an opaque glare.

shield 59 as indicated by numerals 6I. Glare shield 59 is in turn cemented to the exit face of prism 44 in alignment -with the top surface of dial I4 and prevents direct rays of light from passing from the exit face past the edge of dial I4 This shield also tends to divide the light emitted from prism 44 into two parallel planes, the lower of which enters dial I4 through the entrance area defined by the luted portion 50, and the upper portion of which is diffused by the prism over the face of dial I4 to pointer 52 and reiiector 51.

The illumination of the instrument of Figures l to 3 is accomplished in the following manner.

Socket I1 is connected to a suitable source of electrical energy and through conduit I9 lights bulb 35 in boss I8. The normally. divergent rays of light from bulb 35 pass into the bulls-eye lens 46 entering the lens through the convex face and emerging through the at exit face as parallel rays. These rays passing through the portion of lens 46 overlying the protruding end of prism 44 enter prism 44. These last vmentioned rays strike arcuate, total reflecting surface 45 and are bent at Aright angles and pass radially through prism 44. These radially travelling rays of light are divided into parallel horizontal areas by shield 59 and the lower area is projected on the uted edge 'portions 50 of dial I4. The portion 50, being clear, permits the rays of light to enter the interior'of the body of dial I4. Due to the vertical uting of portion 50, the rays enter dial I4 in all directions and are diiiused throughout of dial' I4.

Thesel diffused rays of light pass through dial I4 and strike the exteriorly coated edgesof the dial where each ray is partially reflected in a multiplicity of directions due to the concave reflecting surface provided by the coated edges As a consequence, the dial body glows causing unusually vivid illumination of the white markings and figures due to the absorption of light by the white coating. The white coating on the edge rear surface and face of dial I4 further assures a glowing of the dial material adds further light energy to the markings and gures.

The black coating I furnishes an opaque, dark background, causing the markings and gures to stand out in sharp contrast. As a consequence, the dial markings are vividly illuminated while undesired glare is eliminated due te the indirect nature of the light rays.

The upper area of rays passes above shield 59 and across the face of dial I4. Some of these rays strike pointer 53 and are absorbed by the surface coating while others strike the utings 54 and are diffused throughout the body of the pointer in much the same manner as inthe dial. Still other of the rays, passing across'dial I4 strike corrugated reector ring 51 and are reflected in every direction across dial I4 so as to flood the area above the face of the dial with the interior p indirect light to insure light rays for illuminating the pointer irrespective of its position with respect to the 'rays emerging from prism 45 The portion of prism 44 adjacent to and above shield will glow in the dark so that the instrument is casing readable. although not asreadily as When the bulb 35 is operating.

In vthe modified form of the invention illustrated in Figure 4, the system of lighting is exactly the same as that disclosed in Figures 1 The only diierence in this form of the invention is that'a two part casing IIa is provided. Casing IIa consists of a main body portion 6I and a complementary metallic ring portion 62. The electrical connections in this form of the invention are identical to those described in Figures 1 to 3 up to the point where they enter bore4 21a. At this point, conduits 25 and 30 are carried through apertures 26a and 3Ia (Figure 5) and around openings 63 formed in casing IIa. Ring 62 is provided with a complementary tapped opening 64. A suitable machine screw 65 pasing freely through one opening 63 threads into opening 64 and its head clamps conduit 30 in place'to complete the return circuit from bulb 35 which is mounted in a bore 66. The return circuit is as follows: from bulb 35 through cap 31, metallic ring 62, screw 55, conduit 3B to sheathing 23.

Ring 52is provided with an enlarged opening 61 complementary to the other opening -63 in IIa. A threaded metallic plug 68 is secured in opening 61 and insulated from ring 62. This plug connects with a conduit 69 which serves as the live contact for bulb 35 and is insulated from ring 62 by an insulating member 10. The system of lighting is like that heretofore described.

The modicationshown in Figure 6 discloses a system of illumination wherein the bulls-eyev lens is omitted and a prism 44a similar to prism 44 is used. Prism 44a is a wedge-shaped prism of the same general configuration as prism 44. The small end of prism 44a does not protrude into bore 21 but ends at the side wall. Face 45a is a vertical face forming a continuation of the wall of bore 21. ABulb 35a` of this form of the invention is like bulb 35 except that it is longer so that the filament of the bulb is located directly opposite facer 45a of prism 44a. As a result, light rays from bullb 35a diverge radially from the filament, which for all practical purposes serves as a'point source of light at the center ot face 45a. Due to this structure, the light rays pass through prism 44a in the same manner heretofore described and dial I4 and its associated pointer are similarly illuminated.

A further modification of the invention is disclosed in Figures-7 and 8. In this form of the invention, a casing II exactly like that of Figures 1 to 3 is used. As a consequence, the same reference numerals will be used and lthe detailed description of the casing omitted.

The pointer actuating mechanism I3 of this form of the invention is provided with a metal disk 1I having a dull black finish on its face. Suitable spacer sleeves 12 rest on disk 1I and support a Plexiglas dial 13 in spaced relation to disk 1|. Elongated screws 1i pass through dial 13, sleeves 12 and disk 1l and are threaded into the framework of actuating mechanism i3 to effect a unitary assemblage of these parts. The pointer '15 of this form of the invention consists of a metallic pointer operating in the space between disk 'il and dial 13.

Dia1 13 is made up with a perfectly clear centralportion 16 and with a clear iluted edge portion 50, like the edge portion 5d of Figures 1 to 5. The edge, except portion 50, and the marginal portions of the front and rear surfaces of dial 13 are provided with a coating 1li of white paint, the marginal coating on the face of the dial being somewhat lighter than that on the edge and rear surface. the dial face is then printed with black ink 1li The coated margin of in the manner heretofore described, leaving the" markings and gures white. Certain of these markings and the gures are then coated at 1Q tion 5l is opposite the exit face of prism tt.,

As a consequence, the light rays from prism lll pass through fluted edge portion Sill and below the rear surface of the dial. This passage of the light rays causes the body of the dial at'the" margins to glow as heretofore pointed out in connection with the dial of Figures 1 to 5 and the central portion lo to appear as a lighted eld through which the metallic pointer is viewed.

Since a portion of the light rayspass across the rear surface of dial 13, the area between disk 'H and dial 'i3 receives illumination in addition to that received from clear section 16 of the dial. As a consequence, the pointer iii and any desired name plate or the like di on disk il may be read with facility.l If desired, a reflector, like reflector 51 heretofore described. may be placed in casing Ha at the rear of dial 13.

While the present invention has been described in connection with dial and pointer instruments only, it is capable of use in many other environments. As an illustration of such a further use, the modification of Figure 9 is here presented. In this form of the invention, a rectangular panel 83 of substantial size is illuminated by the system of the present invention. Panel d3 represents a radio control panel havinga clear area St therein and provided with widely separated indicia 85. To effectively illuminate such a panel, it has been found desirable to utilize two or more light sources located at selected points.

Four light sources 86 located centrally on each side of the panel are shown in Figure 9 merely by way of illustration. Each light source contains a bulb, like that heretofore described, held in place by caps 31. These bulbs in turn are asociated with spreading prisms 44 in any one of lthe several manners illustrated in Figures 1 to '7. i

The panel 83 is coated, except for the uted edge portions adjacent each prism and portion 84, with a primary coating l! of white paint. The face or top surface is provided with an opaque coating 89 with the -indicia exposed in white. Coating 89 may consist of black printing ink, decorative wood finishes or any desired substance having suilicient opacity. The several light bulbs when properly located will cause the body to glow uniformly and evenly illuminate the indicia at all points in theJnanner heretofore described in detail.

The invention may be embodied in other specic forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and al1 changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by l United States Letters Patent is:

1. An indicating instrument comprising a casing, a dial, a pointer, a lamp mounted in said casing adjacent an edge portion of said dial, and means to cause said lamp to illuminate said dial and pointer, comprising a lens to parallel rays of light emitted from said lamp, a prism to disperse said light rays substantially evenly through the body of said dial and above said dial toward said pointer, and a reflector surrounding said pointer and reflecting light toward said pointer.

2. .An indicating instrument comprising a casing, a smooth surfaced dial having a light transmltting body, a smooth translucent coating ou said dial providing indicia Outlined by an opaque covering on said coating, a source of light mounted in said casing adjacent an edge portion of said dial, a translucent pointer having a serrated under surface movable over said dial, and means to cause rays of light from said lamp to be substantially evenly distributed through the body of said dialand to be reflected on said surfaces of said pointer from substantially every direction to cause it to stand out against said opaque covering for said dial.

3. An indicating instrument, comprising a dial of translucent material, means to ood the body oi said dial with light, a reflective coating on the back of said dial, a translucent coating and a superposed opaque coating on a portion of the front of said dial, the latter coating being interrupted to expose said translucent coating and thus provide indicia, Ia pointer movable over the front ci said dial means to illuminate said indicia and pointer without causing shadows including a reflecting ring substantially surrounding said pointer and said dial and means to cause light rays to reach said ring in planes parallel to the surface of said dial'.

4. An indicating instrument, comprising a dial of translucent material, a lamp disposed adjacent an edge of said dial, means to parallel certain ofthe rays of said light, means to cause a portion of said parallel rays of said lamp to be diffused substantially evenly through the body of said dial, means to cause the other of said parallel rays to enter the space in front o! said dial only in planes parallel to said dial, a pointer in said space, means to redect the light in said space toward said pointer, and means to cause said first named parallel rays to illuminate only the indicia of said dial whereby glare is minimized. 4

5. An opticall system lor use in an indicating instrument having a dial illuminated by a source of light mounted in the instrument casing adjacent the periphery o1'4 the dial. comprising a. lens to parallel the light rays from said source of light and a prism to reflect said paralleled rays into the body of the dial substantiauy evenly, said prism having a curved reecting surface and a curved light emitting surface of substantially g equal angular length, said angle being sufciently large so as to substantially include the width of the dial.

6. An individually lighted instrument, comprising a casing, a miniature lamp mounted in said casing, a dial of translucent material having a surface coated by a translucent coatingand a superposed opaque covering applied to portions of said translucent coating so as to loutline translucent indicia., a pointer movable over said dial,

and a lens and a prism interposed between said over the dial, a reflector ring substantially sur-l rounding said pointer and said dial, and means between said dial and said illuminating means to direct light from said illuminating means into the body of the dial and into the space surrounding said pointer to illuminate said ring and pointer in planes parallel to the dial, whereby the instrument is lighted without glare and without causing the pointer to cast shadows. Y

8. An indicating instrument comprising a dial having a light transmitting body and a smooth substantially plane face; translucent indicia on said face and an opaque covering on said face outlining said indicia: a translucent indicator element movable over said dial with said covering as a background; a light source, and means adjacent an edge of said body for dispersing a part of'the light from said source into the interior of said body whereby said indicia are illuminated, said means also being constructed and arranged so as to direct light rays in a plane parallel to said dial and in the plane of said indicatori element.

9. An indicating instrument, comprising a transparent dial having translucent indicia outlined by an opaque covering; a translucent pointer spaced from and movable over said dial in a plane parallel therewith, said pointer having a polygonal cross-section with one face parallel to the plane of said dial and provided with a number of serrations; a light source adjacent an edge of said dial; means Vfor paralleling a portion of the light rays from said'source and for distributing said paralleled rays in the plane of said dial and in the plane of said spaced pointer, whereby said translucent indicia and said pointer are clearly illuminated.

10. An indicating instrument comprising a casing, a dial mounted in said casing having a light i transmitting body, a pointer movable over said dial, said pointer being shaped to present reflecting surfaces, a lamp disposed in said casing adjacent an edge of the dial,` means to parallel certain rays of said lamp, means to disperse some of said paralleled rays of light through the body of said dial and other of said rays into the plane of the pointer, and a substantially cylindrical reiiector substantially surrounding said pointer and dial to reect light rays onto the dial and into the plane of the pointer.

MAIHMIHAN WILLIAM E. PFEFFER.y 

